Low voltage lighting fixtures which take advantage of the higher efficiencies and improved color temperatures of halogen filled incandescent lamps are in wide use. Due to the high current levels required for a given lamp wattage at low voltage, it is desireable to provide transformation of the high line voltage to low lamp voltage as close to the lamp as possible. Most presently used fixtures provide a transformer in an enclosure that is adjacent to but separate from the lamp housing to keep the lamp heat away from the transformer.
There are a few fixtures in use that presently include a low voltage transformer in the fixture housing, but in order to keep the transformer within thermal operating limits the housing then must be almost entirely comprised of ventilation holes in the form of louvers or perforated sheet metal contruction. This permits the intrusion of dirt, dust and moisture directly into the fixture along with the convection air, and usually results in an ugly external appearance in which light leaks from every cooling aperture. This phenomenon is accentuated by the use of halogen lamps having glass dichroic reflectors, in which a portion of the light in the visible spectrum and most of the infrared is passed through the lamp reflector and into the fixture housing.